Cooling device for an electric component

ABSTRACT

A cooling device has a cooling element ( 3 ) and a pressing device ( 4 ) which presses the component ( 1 ) against the cooling element ( 3 ). The pressing device ( 4 ) is resilient and is connected to the cooling element in a positive fit in order to produce fixing means which fix the component ( 1 ) to the cooling element in a reliable manner, the fixing means being easy to produce and compact.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of co-pending InternationalApplication No. PCT/EP2004/011874, filed Oct. 20, 2004, which designatesthe United States, and claims priority to German application number DE103 53 849.6 filed Nov. 18, 2003, the contents of which are herebyincorporated in their entirety by reference.

TECHNICAL FIELD

The invention relates to a cooling device for an electric component.

BACKGROUND

Such a cooling device which is revealed in DE 199 42 915 A1 comprises anelectric component having an insulating and thermally conductivesubstrate. A plurality of power semiconductor modules are arranged onthe top side of the substrate and are electrically connected toconductor track structures.

The underside of the substrate functions as a heat-dissipating contactarea with which the substrate is pressed onto a heat sink with the aidof a pressure-exerting device in order to be able to dissipate powerlosses which occur in the form of heat during operation of thecomponent. The pressure-exerting device is formed from a plurality ofelectrically conductive pressure pieces which are supported, on the onehand, on a covering printed circuit board and, on the other hand, on thesubstrate. The pressure-exerting device is of relatively complicateddesign and is difficult to assemble.

A cooling device for an electric component having a pressure-exertingdevice, which is in the form of a resilient holding clip and has ananchoring region that is received by a barb of the cooling element, isalso known.

SUMMARY

A cooling device for an electric component may comprise a coolingelement and a flexible pressure-exerting device which presses thecomponent onto the cooling element in a force-locking manner.

A cooling device for an electric component may also comprise a coolingelement and a flexible pressure-exerting device which presses thecomponent onto the cooling element in a force-locking manner, whereinthe pressure-exerting device has a slotted sleeve which is pressed intoan opening in the cooling element.

A cooling device for an electric component may also comprise a means forcooling the electric component and a means for flexibly exertingpressure on the electric component to press the electric component ontothe cooling element in a force-locking manner.

A method of cooling an electric component may comprise the steps ofproviding a cooling element; arranging an electric component on thecooling element; and exerting pressure by means of a flexible deviceonto the cooling element in a force-locking manner to press thecomponent onto the cooling element.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is explained in more detail below with referenceto the exemplary embodiments which are shown in the figures, in which:

FIG. 1 shows a cross section of an embodiment of a cooling device for anelectric component,

FIGS. 2 a, 2 b, 2 c, and 2 d show various views of a pressure-exertingdevice, and

FIGS. 3 a, 3 b, and 3 c show various views of another embodiment of acooling device.

DETAILED DESCRIPTION

According to an embodiment, a resilient pressure-exerting device isconnected to the cooling element in a force-locking manner, thusrealizing extremely simple force transmission between the component andthe cooling element. In comparison with other conceivable connections,for example screw connections, the connection requires only a very smallamount of space and does not require any additional fastening parts.Very simple assembly and, if desired, also disassembly are thuspossible. A pressure-exerting device may preferably comprises one part.

The pressure-exerting/fastening device may advantageously have one ormore suitable elements for a force-locking connection, said elementsbeing introduced, for example, into a corresponding opening in thecooling element. In this case, the connecting elements are oversized incomparison with the opening. An embodiment provides for thepressure-exerting device to have a resilient connecting element which ispressed into an opening in the cooling element. With respect to designand production engineering, the connecting element may be a slottedsleeve whose oversized dimension can be elastically and thus reversiblyreduced to the width of the opening as it is being pressed into theopening. The spring force and the diameter of the sleeve make itpossible to set the static friction force to such an extent thatacceleration forces, as are caused, for example, by vibrations, do notresult in the connection being released.

In special applications, for example in the case of high-temperatureand/or vibration-loading ambient conditions, it may be desirable toadditionally safeguard the connection. To this end, one embodiment of acooling device provides for the connection between the pressure-exertingdevice and the cooling element to be safeguarded using a lock which actsin the disassembly direction. The lock may be a barb which increases thefriction forces between the participants in the connection.

One embodiment which is preferred in terms of assembly provides for thepressure-exerting device to have a resilient clip which can be used topress the component onto the cooling element and which has a resilientelement at both ends.

FIG. 1 shows a first cooling device for an electric component (powersemiconductor module) 1. The component 1 has a heat-dissipating area 2which is used to establish intimate thermally conductive contact betweensaid component and a cooling element 3. For this purpose, use is made ofa pressure-exerting device 4 which is permanently connected to thecooling element 3 in a force-locking manner and exerts a contact forceF1 on the power semiconductor module 1. The figure diagrammaticallyreveals an external electrical connection 5 of the power semiconductormodule.

The pressure-exerting device 4 is composed of a spring-elastic material,for example a leaf-spring steel, and comprises a resilient clip 8 whichpresses onto the power semiconductor module 1 with the contact force F1.In order to be fastened in a hole 9 of the cooling element 3, thepressure-exerting device 4 has at least one force-transmitting element(connecting element) 10. The latter is preferably formed from acylindrical spring sleeve 11 which is formed from leaf-spring steel andhas a longitudinal slot. The latter provides the force-transmittingelement with the desired radial spring force. This force may be set onan application-oriented basis, by means of suitable dimensioning(length, oversized diameter, insertion depth) and diameters, in such amanner that the (static) friction forces or clamping forces F2, whichare produced thereby, between the wall of the hole 9 and the surface ofthe spring sleeve 11 ensure that the latter is permanently and reliablyfixed in the hole. This ensures that the counterforce to the contactforce F1 is transmitted to the cooling element 3. For the purpose ofadditional safeguarding, if necessary, provision is made of a lock inthe form of a barb 14 which hinders movement (in the disassemblydirection D and additionally hinders rotation in the case of acylindrical spring sleeve).

FIG. 2 a separately shows a pressure-exerting device 20 having asleeve-shaped resilient element 21 as the fastening device, a pressureclip 22 and a barb 23. As FIG. 2 b illustrates, the pressure-exertingdevice comprises a total of two resilient elements 21, 24 which are eachformed as longitudinally slotted sleeves at the ends of the clip 22. Theillustration in FIG. 2 c and the perspective illustration in FIG. 2 dshow that, in order to reinforce the central part 27 which adjoins theclip 22, said central part is folded at the lower join of the sleeves21, 24. This fold 28 thus runs parallel to the clip 22.

FIGS. 3 a, 3 b and 3 c show another embodiment of a cooling device, inwhich two parallel leaf springs 30, 31 which are arcuate in the unloadedstate press onto a power semiconductor module 33 (FIGS. 3 b, 3 c). Thespring ends 30 a, 30 b and 31 a, 31 b are connected, via twocrossmembers 34, 35, to form a spring frame.

In the respective central region of the crossmembers, provision is madeof respective resilient elements 36, 37 which are configured, inprinciple, as described above and are fixed in two holes 38, 39 of acooling element 40 by means of a force-locking connection (FIGS. 3 b and3 c).

The cooling device is distinguished by simple assembly (anddisassembly), during which, in principle, only the elements forproducing the force-locking connection need to be inserted into thecorresponding receptacles of the participant in the connection, whichreceptacles are very easy to produce by means of drilling, for example.Additional parts, for example screws, are not required and the amount ofspace required by this force-locking connection is very small.

LIST OF REFERENCE SYMBOLS

-   D Disassembly direction-   F1 Contact force-   F2 Clamping forces-   1 Component (power semiconductor module)-   2 Heat-dissipating area-   3 Cooling element-   4 Pressure-exerting device-   5 Connection-   8 Clip-   9 Hole-   10 Force-transmitting element-   11 Spring sleeve-   14 Barb-   20 Pressure-exerting device-   21 Resilient element-   22 Pressure clip-   23 Barb-   24 Resilient element-   27 Central part-   28 Fold-   30, 31 Leaf springs-   30 a, 30 b Spring ends-   31 a, 31 b Spring ends-   33 Power semiconductor module-   34, 35 Crossmembers-   36, 37 Resilient elements-   38, 39 Holes-   40 Cooling element

1. A cooling device for an electric component comprising a coolingelement and a flexible pressure-exerting device which presses thecomponent onto the cooling element in a force-locking manner.
 2. Thecooling device as claimed in claim 1, wherein the pressure-exertingdevice has a resilient element which is pressed into an opening in thecooling element.
 3. The cooling device as claimed in claim 2, whereinthe resilient element is a slotted sleeve.
 4. The cooling device asclaimed in claim 1, wherein the connection between the pressure-exertingdevice and the cooling element is safeguarded using a lock.
 5. Thecooling device as claimed in claim 4, wherein the lock is a barb.
 6. Thecooling device as claimed in claim 1, wherein the pressure-exertingdevice has a resilient clip which can be used to press the componentonto the cooling element and which has a resilient element at both ends.7. A cooling device for an electric component comprising a coolingelement and a flexible pressure-exerting device which presses thecomponent onto the cooling element in a force-locking manner, whereinthe pressure-exerting device has a slotted sleeve which is pressed intoan opening in the cooling element.
 8. The cooling device as claimed inclaim 7, wherein the connection between the pressure-exerting device andthe cooling element is safeguarded using a lock.
 9. The cooling deviceas claimed in claim 8, wherein the lock is a barb.
 10. The coolingdevice as claimed in claim 7, wherein the pressure-exerting device has aresilient clip which can be used to press the component onto the coolingelement and which has a resilient element at both ends.
 11. A coolingdevice for an electric component comprising a means for cooling theelectric component and a means for flexibly exerting pressure on theelectric component to press the electric component onto the coolingelement in a force-locking manner.
 12. The cooling device as claimed inclaim 11, wherein the means for exerting pressure has a resilientelement which is pressed into an opening in the means for cooling. 13.The cooling device as claimed in claim 12, wherein the resilient elementis a slotted sleeve.
 14. The cooling device as claimed in claim 11,wherein the connection between the means for exerting pressure and themeans for cooling is safeguarded using a lock.
 15. The cooling device asclaimed in claim 14, wherein the lock is a barb.
 16. The cooling deviceas claimed in claim 11, wherein the means for exerting pressure has aresilient clip which can be used to press the component onto the meansfor cooling and which has a resilient element at both ends.
 17. A methodof cooling an electric component comprising the steps of: providing acooling element; arranging an electric component on the cooling element;and exerting pressure by means of a flexible device onto the coolingelement in a force-locking manner to press the component onto thecooling element.
 18. The method as claimed in claim 17, furthercomprising the step of pressing a resilient element into an opening inthe cooling element.
 19. The method as claimed in claim 18, wherein theresilient element is a slotted sleeve.
 20. The method as claimed inclaim 17, further comprising the step of safeguarding a connectionbetween a pressure-exerting device and the cooling element by a lock.21. The method as claimed in claim 20, wherein the lock is a barb. 22.The method as claimed in claim 17, further comprising the step of usinga resilient clip to press the component onto the cooling element whereinthe resilient clip has a resilient element at both ends.